Bug 942729, Part 1: Re-enable TLS False Start, r=mcmanus

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extra : rebase_source : 9908b1cbc3a30e9868739a10a705de8dbf30c5e1
Bug 942729, Part 2: Remove unused expected symmetric cipher mechanism, r=briansmith

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extra : rebase_source : 9630808b663d6a670c2e45d242177a640817f2ee